Seasonal Changes Research Articles

Counteracting greenhouse gas and aerosol influences intensify global water seasonality over the past century

Variations in water availability seasonality significantly impact society and ecosystems. While many studies have focused on mean or extreme precipitation, the response of water availability seasonality, influencing yearly water distribution beyond individual extremes, to human-induced climate change remains underexplored. Here we examine global and regional water availability seasonality changes from 1915 to 2014, quantifying how anthropogenic greenhouse gases and aerosols have influenced these variations using reanalysis and simulations from Coupled Model Intercomparison Project Phase 6. Despite large spatiotemporal uncertainties due to regional variability and model assumptions, we find that greenhouse gases significantly amplify the seasonality, while aerosols reduce it. Given that the positive effects of greenhouse gases surpass the aerosols’ negative effects, the counterbalancing influences have led to an overall enhancement in seasonality of water availability over the past century. This trend is expected to continue in the future as greenhouse gases-induced warming continues to rise and aerosol levels decline.

Is it worth paying attention to actinedid mites in agricultural fields?

Agricultural management increases the seasonal dynamics of soil-dwelling organisms compared to natural habitats. Our knowledge is very poor about the relationship between seasonal changes of soil microorganisms and the microbivorous soil arthropods. To reveal these connections, we have to know more about the seasonal changes of soil-dwelling microarthropods in croplands. Actinedid mites are rarely the subject of synecological studies, however, this group regularly reaches the dominant part of mite assemblages in agro-ecosystems. In this study, we investigated the seasonal density changes of actinedid mites from two independent studies of agricultural fields. Soil samples were taken from maize and wheat fields for two years, and from newly established meadows for one year in summer and autumn in Hungary. Soil-dwelling mites were enumerated and identified at the suborder level and soil parameters were measured. Actinedid mites dominated most of our soil samples. The density of Endeostigmata was the highest in the summer and the density of Heterostigmata was the highest in the autumn within one year among different crop species, soil types, and years. Endeostigmatid mites had negative relationships with soil nitrogen parameters and positive with soil moisture. Heterostigmatid mites had various relationships with soil moisture. The ecology of actinedid mites is under-examined but their high number in agricultural fields may justify the fact that they should receive more attention. We assume that Actinedida, mainly Endeostigmata and Heterostigmata are worth to investigate in croplands as a starting point to reveal the connection between the seasonality of soil mites and soil microbiota.

Space-based long term condition monitoring of cold region pavement with PS-InSAR

The durability of cold-climate pavement is affected by ground frost heave and thaw settlement. Field monitoring of pavement elevation changes remain challenging and expansive. This study demonstrates space-based Interferometric Synthetic Aperture Radar (InSAR) technology as a potential way to monitor seasonal pavement elevation change in cold region. Traditional InSAR applications, which were designed for geoscience scales, do not achieve the needed sensitivity or spatial resolution for pavement engineering applications. The testbed used is a cold-region airport located in Qinghai Province, China. The site contains heterogeneous ground conditions in an area of 4km × 6km. Analyses were conducted using 132 ascending and 149 descending C-band InSAR images from the Sentinel-1 satellite. InSAR algorithm based on Persistent scatterers (PS-InSAR) were implemented for data analyses. Time series displacement across five distinct persistent scatterers (PSs) groups at different locations were obtained. From these, three main seasonal vertical ground deformation patterns were identified, each reflecting the diverse subsurface soil characteristics across the sites. The ground elevation changes were decomposed into baseline trend and seasonal changes. The results of seasonal ground deformations allowed to differentiate the ground soils as frost-susceptible and non-frost-susceptible, an important information for geotechnical site investigation. This helps identify areas of pavement subjected to frost heave and thaw weakening. The study demonstrates that potential of space-based InSAR technology to achieve spatial resolution and sensitivity for monitoring the performance of cold region pavement. The results allow to identify areas of pavement vulnerable to cold region climate and climate change.

Contrastive Dual-Pool Feature Adaption for Domain Incremental Remote Sensing Scene Classification

Remote sensing image classification has achieved remarkable success in environmental monitoring and urban planning using deep neural networks (DNNs). However, the performance of these models is significantly impacted by domain shifts due to seasonal changes, varying atmospheric conditions, and different geographical locations. Existing solutions, including rehearsal-based and prompt-based methods, face limitations such as data privacy concerns, high computational overhead, and unreliable feature embeddings due to domain gaps. To address these challenges, we propose DACL (dual-pool architecture with contrastive learning), a novel framework for domain incremental learning in remote sensing image classification. DACL introduces three key components: (1) a dual-pool architecture comprising a prompt pool for domain-specific tokens and an adapter pool for feature adaptation, enabling efficient domain-specific feature extraction; (2) a dual loss mechanism that combines image-attracting loss and text-separating loss to enhance intra-domain feature discrimination while maintaining clear class boundaries; and (3) a K-means-based domain selector that efficiently matches unknown domain features with existing domain representations using cosine similarity. Our approach eliminates the need for storing historical data while maintaining minimal computational overhead. Extensive experiments on six widely used datasets demonstrate that DACL consistently outperforms state-of-the-art methods in domain incremental learning for remote sensing image classification scenarios, achieving an average accuracy improvement of 4.07% over the best baseline method.

Pervasive glacier retreats across Svalbard from 1985 to 2023.

A major uncertainty in predicting the behaviour of marine-terminating glaciers is ice dynamics driven by non-linear calving front retreat, which is poorly understood and modelled. Using 124919 calving front positions for 149 marine-terminating glaciers in Svalbard from 1985 to 2023, generated with deep learning, we identify pervasive calving front retreats for non-surging glaciers over the past 38 years. We observe widespread seasonal cycles in calving front position for over half of the glaciers. At the seasonal timescale, peak retreat rates exhibit a several-month phaselag, with changes on the west coast occurring before those on the east coast, coincident with regional ocean warming. This spatial variability in seasonal patterns is linked to different timings of warm ocean water inflow from the West Spitsbergen Current, demonstrating the dominant role of ice-ocean interaction in seasonal front changes. The interannual variability of calving front retreat shows a strong sensitivity to both atmospheric and oceanic warming, with immediate responses to large air and ocean temperature anomalies in 2016 and 2019, likely driven by atmospheric blocking that can influence extreme temperature variability. With more frequent blocking occurring and continued regional warming, future calving front retreats will likely intensify, leading to more significant glacier mass loss.

Metabolic skinflint or spendthrift? Insights into ground sloth integument and thermophysiology revealed by biophysical modeling and clumped isotope paleothermometry

Remains of megatheres have been known since the 18th -century and were among the first megafaunal vertebrates to be studied. While several examples of preserved integument show a thick coverage of fur for smaller ground sloths living in cold climates such as Mylodon and Nothrotheriops, comparatively very little is known about megathere skin. Assuming a typical placental mammal metabolism, it was previously hypothesized that megatheres would have had little-to-no fur as they achieved giant body sizes. Here the “hairless model of integument” is tested using geochemical analyses to estimate body temperature to generate novel models of ground sloth metabolism, fur coverage, and paleoclimate with Niche Mapper software. The simulations assuming metabolic activity akin to those of modern xenarthrans suggest that sparse fur coverage would have resulted in cold stress across most latitudinal ranges inhabited by extinct ground sloths. Specifically, Eremotherium predominantly required dense 10 mm fur with implications for seasonal changes of coat depth in northernmost latitudes and sparse fur in the tropics; Megatherium required dense 30 mm fur year-round in its exclusive range of cooler, drier climates; Mylodon and Nothrotheriops required dense 10–50 mm fur to avoid thermal stress, matching the integument remains of both genera, and further implying the use of behavioral thermoregulation. Moreover, clumped isotope paleothermometry data from the preserved teeth of four genera of ground sloth yielded reconstructed body temperatures lower than those previously reported for large terrestrial mammals (23 ± 5–32 ± 3° C). This combination of low metabolisms and thick fur allowed ground sloths to inhabit various environments.

SHELL MICROSTRUCTURE AND MINERALOGY OF THE MOLLUSC SPECIES <em>ANADARA UROPIGIMELANA</em> (BORY DE SAINT-VINCENT, 1827), <em>TIVELA STEFANINII</em> (NARDINI, 1933) AND <em>OLIVA BULBOSA</em> (RÖDING, 1798)

Mollusc shells are composite structures made of calcite and/or aragonite crystals and biopolymers, arranged in a great variety of microstructures. The formation of shell microstructures is affected by environmental and physiological factors and differences among microstructural types are believed to be of phylogenetic and adaptive biomechanical significance. Here, we characterise and illustrate for the first time, through SEM and XRD analyses, the shell microstructure and mineralogy of specimens of the bivalves Anadara uropigimelana (Bory de Saint-Vincent, 1827) and Tivela stefaninii (Nardini, 1933), and of the gastropod Oliva bulbosa (Röding, 1798), collected in the Upper Holocene HAS1 settlement and in a shell midden in the Khor Rori Archaeological Park (Oman). Anadara uropigimelana shows an aragonitic shell with an outer crossed lamellar layer, an inner complex crossed lamellar layer and an irregular simple prismatic pallial myostracum; periodic bands of dendritic nondenticular composite prisms occur in the outer part of the outer layer, reflecting seasonal changes in water temperatures and growth rates. Shells of Tivela stefaninii are aragonitic with an outer composite prismatic layer, a middle crossed lamellar layer and an inner complex crossed lamellar layer, whereas those of Oliva bulbosa are characterised by an irregular alternation of aragonitic crossed lamellar layers; a transitional layer defined by the occurrence of tidally controlled growth lines, a crossed lamellar callus and a myostracal layer are also described are also described in Oliva bulbosa. With this investigation, we provide novel microstructural and mineralogical data on these poorly known mollusc species, providing useful characters for phylogenetic, evolutionary, crystallographic, and palaeoenvironmental studies.

A Study of Member Displacement According to Seasonal Climate of the Sungnyemun Gate, a Korean Wooden Architectural Heritage Site

This study analyzes the results of a displacement measurement of the Sungnyemun Gate’s structural members, such as column, girder, and hip rafter, carried out by the National Institute of Cultural Heritage for about 10 years from December 2013 to October 2022. Through this, we attempt to examine the behavior of wooden architectural heritage sites according to seasonal changes and infer the factors influencing structural deformation. As a result of the analysis, it was confirmed that the structural members of the Sungnyemun Gate, including the columns, girders, and hip rafters, continued to move and that the displacement of members was accumulated, and the structure was deformed. It was also confirmed that member displacements accumulated in a specific direction. In the case of the Sungnyemun Gate, the column leaning south, the hip rafters’ endpoint sagging, and the girders’ center deflecting were continuously observed. Furthermore, the behavior of wooden architectural heritage sites, where displacement accumulates as it undergoes repeated deformation and recovery according to seasonal changes, was also revealed in detail. The deformation of the Sungnyemun Gate’s members shows a pattern that reflects the mechanical properties of wood, which repeatedly increases and decreases displacement depending on the season. However, seasonal deformation did not appear the same in all the members. Even the same member has an uneven drying speed due to differences in the amount of sunlight it receives depending on its location, which leads to uneven distribution of deformation. The significance of this study is that it examined the behavior of a wooden architectural heritage site in detail based on the quantitative results of long-term measurements and prepared primary data for the future management of wooden architectural heritage sites.

How the fish community structure change with seasons in Zhoushan Fishing Ground, China?

Understanding seasonal variations in fish communities is important for fishery resources conservation and management in fishery economic zones. However, there are still knowledge gaps regarding to the differential responses of fish functional traits to various disturbances. Here, we sampled fish communities of 20 sites during autumn (November 2023) and spring (April 2024) in Zhoushan Fishing Ground. Taxonomic diversity (TD), functional diversity (FD), and functional redundancy (FR) were calculated to investigate the state of the fish communities and their seasonal changes. Beta diversity was calculated based on the pairwise communities of spring and autumn and decomposed into turnover and nestedness proportions, to investigate the dissimilarities of the fish communities between the two seasons and their drive mechanisms. We also applied R-mode linked to Q-mode (RLQ) and fourth-corner methods to test the relationships between fish functional traits and environmental variables (trait-environment relationships). These results showed that the mean values of taxonomic and functional beta diversities were 0.852 and 0.769, respectively, which indicate that taxonomic and functional structures of the fish communities have high dissimilarities between spring and autumn. However, the taxonomic and functional structures showed different ecological processes of seasonal changes with the former were mainly driven by species turnover (occupied 89.9% of the total dissimilarity) and the latter were driven by both functional turnover and nestedness (occupied 57.9% and 42.1% of the total dissimilarity, respectively). Species occurrence, environmental variables, and functional traits matrices were closely correlated, which mainly result from the significant trait-environmental relationships. Combining with TD, FD, and FR, we concluded that the fish communities in autumn had higher resistance to environmental changes than in spring. Our findings are accepted to serve as a basis for fishery management.

Body Condition and Blood Biochemistry of Free-Range Caiman latirostris in Northeast Brazilian Atlantic Forest.

The Atlantic Forest broad-snouted caiman (Caiman latirostris) inhabits regions within one of the world's most ecologically diverse ecosystems, yet few studies have explored the relationship between body condition, blood biochemistry, and environmental factors in the wild. Our study investigated the effects of sex, ontogeny, habitat, and environmental variables on the body condition and blood biochemistry of free-ranging caimans from the state of Alagoas, Northeast Brazil. From 2020 to 2022, we captured 75 caimans across three sites in different seasons. Results revealed sex-specific responses to seasonal and Interannual weather changes, with females showing higher body condition in the wet season, while males peaked in the dry season. Elevated glucose, total protein, albumin, triglycerides, and fructosamine were linked to higher body condition and larger individuals, while elevated aspartate aminotransferase to low body condition. Seasonal rainfall influenced blood parameters, with the dry season associated with higher creatinine, calcium, and alanine aminotransferase levels, and the wet season with higher total protein, sodium, and potassium. Differences in glucose, alkaline phosphatase, and gamma-glutamyl transferase across sites pointed to physiological effects of human activities. Blood biochemical values varied widely, with some exceeding reported species ranges. These findings highlight the need to interpret physiological data within the context of local habitat and environmental conditions. Conservation strategies should go beyond species presence and habitat preservation, incorporating pollution control. Our study advances understanding of Caiman latirostris ecophysiology, offering valuable insights for the conservation and management of crocodilian populations in both wild and captive environments.

Profound Changes in the Seasonal Cycle of Sea Level Along the United States Mid‐Atlantic Coast

AbstractThe monthly mean sea level along the U.S. Mid‐Atlantic Coast varies seasonally, reaching a minimum in January and a maximum in September during the 1960–2020 period. However, this seasonal cycle has changed significantly on multi‐decadal timescales. In the last two decades, the annual minimum has shifted from January to February. The amplitude of seasonal changes increased by 65% from 14.16 cm in 1980–1999 to 23.16 cm in 2000–2020. Even more concerning, the maximum sea level in September rose by 82%, from 6.81 to 12.38 cm, potentially exacerbating coastal flooding over the past 20 years. A two‐layer ocean model effectively replicates both the phase and magnitude of the observed changes and attributes these shifts to changes in wind stress near the coast, with relatively minor influence from deep ocean forcing. Both alongshore and cross‐shore wind stress changes are found to contribute to changes in the sea level's seasonal cycle.

Seasonal changes of mélange thickness coincide with Greenland calving dynamics

Iceberg calving is a major contributor to Greenland’s ice mass loss. Ice mélange, tightly packed sea ice and icebergs, has been hypothesized to buttress the calving fronts. However, quantifying the mélange buttressing force from field observations remains a challenge. Here we show that such quantification can be achieved with a single field measurement: thickness of mélange at the glacier terminus. We develop a three-dimensional discrete element model of mélange along with a simple analytical model to quantify the mélange buttressing using mélange thickness data from ArcticDEM over 32 Greenland glacier termini. We observed a strong seasonality in mélange thickness: thin mélange (averaged thickness 34−15+17 m) in summertime when terminus retreats, and thick mélange (averaged thickness 119−37+31 m) in wintertime when terminus advances. The observed seasonal changes of mélange thickness strongly coincide with observed Greenland calving dynamics and the modeled buttressing effects.

Isotopic variability of the invasive blue crab Callinectes sapidus in the Gulf of Cadiz: Impacts and implications for coastal ecosystem management.

The variability in trophic position and carbon isotopic signatures can provide information about their dietary flexibility and its ability to adapt to changing environmental conditions. The impact of the invasive blue crab Callinectes sapidus was assessed by estimating its trophic position and isotopic niche using stable isotopes (δ1³C, δ1⁵N, δ³⁴S) across different invaded Atlantic coastal areas. This study, the first of its kind in the eastern Atlantic range, reveals the crab's omnivorous behavior with a wide trophic position (TP=2-4), consistent with findings from its native range. Significant spatial variability in trophic roles was observed between habitats, with salt marshes showing enriched δ1³C and lower TP due to differences in primary producers like Spartina detritus and phytoplankton. Estuaries exhibited higher and broader δ1⁵N and TP ranges, influenced by prey availability and anthropogenic nitrogen inputs, that implies a significant impact on marine benthic and pelagic animal communities. Seasonal changes in the Guadalquivir estuary, linked to overwintering and brooding migrations, showed sexual differences in isotopic signatures, with males more enriched in δ1⁵N than females, indicating varied prey availability or metabolic differences. Overall, the Atlantic invaded range displayed broader and lower TP compared to the Mediterranean, underlining the blue crab's flexible and diverse trophic role across different habitats and trophic levels. The variability in trophic position and carbon isotopic signatures reflects the dietary flexibility of this invasive species and its potential effects on native fauna. These findings emphasize the need to consider trophic interactions in ecosystem management and conservation efforts.

A comparison of seasonal flexibility in pectoralis muscle fiber type and enzyme activity in migratory and resident sparrow species

The pectoralis muscle in birds is important for flight and thermogenesis. In migratory songbirds this muscle exhibits seasonal flexibility in size, but whether this flexibility reflects changes in muscle fiber type has not been well documented. We investigated how seasonal changes in photoperiod affected pectoralis muscle fiber type and metabolic enzymes, comparing among three closely-related sparrow species: two seasonal migrants and one year-round, temperate climate resident. We quantified fast oxidative glycolytic (FOG) and fast glycolytic (FG) fibers histologically, and measured activities of citrate synthase (CS) and lactate dehydrogenase (LDH) in the pectoralis muscle of the three species that were acclimated to long- or short-daylight length conditions. In all species FOG was the predominant fiber type, but song sparrows had FG fibers regardless of daylight length. By contrast, Lincoln's sparrows incorporated FG fibers only under short-daylight length onditions, and house sparrows did not significantly express FG fibers, regardless of conditions. Both migratory species increased LDH activity in short-daylight conditions, but did not alter CS activity. In contrast, resident house sparrows did not alter CS or LDH activity with changes in daylight length. Our findings suggest that the presence of FG fibers is important for seasonal flexibility in LDH activity. Additionally, migratory species exhibited seasonal flexibility in muscle fiber type and enzyme activity, presumably to support migratory flight, while the resident species did not exhibit such seasonal flexibility, suggesting that this consistent phenotype is important year-round, despite changing thermogenic requirements.

Unravelling viral ecology and evolution over 20 years in a freshwater lake.

As freshwater lakes undergo rapid anthropogenic change, long-term studies reveal key microbial dynamics, evolutionary shifts and biogeochemical interactions, yet the vital role of viruses remains overlooked. Here, leveraging a 20 year time series from Lake Mendota, WI, USA, we characterized 1.3 million viral genomes across time, seasonality and environmental factors. Double-stranded DNA phages from the class Caudoviricetes dominated the community. We identified 574 auxiliary metabolic gene families representing over 140,000 auxiliary metabolic genes, including important genes such as psbA (photosynthesis), pmoC (methane oxidation) and katG (hydrogen peroxide decomposition), which were consistently present and active across decades and seasons. Positive associations and niche differentiation between virus-host pairs, including keystone Cyanobacteria, methanotrophs and Nanopelagicales, emerged during seasonal changes. Inorganic carbon and ammonium influenced viral abundances, underscoring viral roles in both 'top-down' and 'bottom-up' interactions. Evolutionary processes favoured fitness genes, reduced genomic heterogeneity and dominant sub-populations. This study transforms understanding of viral ecology and evolution in Earth's microbiomes.

Seasonal variation in roost climate and emergence behaviour in a colony of the highly gregarious wrinkle-lipped free-tailed bat (Mops plicatus)

ABSTRACT As obligate nocturnal mammals, most bats spend the day hiding in dark shelters, sometimes as gregarious colonies. Roosting in such large colonies may have the advantage of reducing thermoregulatory costs, as the heat dissipated by thousands of bodies raises the temperature of the cave interior. However, bats in large aggregations may also suffer from increased predation risk. Here we studied the effect of a highly gregarious Palaeotropical bat, the wrinkle-lipped free-tailed bat (Mops plicatus), on cave temperature and the factors that influence its emergence behaviour. We studied cave temperature, prey abundance, emergence behaviour and attack rates by birds of prey during colony emergence. The study was made at Khao Wongkot Cave, counting more than one million individuals. In all seasons, we observed that the presence of M. plicatus caused relatively higher temperatures of around 30°C inside the cave, while temperatures outside were lower and more variable. This suggests that the body heat of aggregated bats raised the temperature inside the cave, presumably close to the thermo-neutral zone at the roosting sites of bats. Arthropod abundance was highest during late pregnancy/early lactation and lowest during late lactation/post lactation. Bats emerged earliest during the late wet season and latest during the hot season. During periods of high predation risk, bats always emerged as a column, whereas during periods of low predation risk (hot and early wet seasons), individual bats left first, before a column of bats formed, 10 to 20 min after the first individuals exited the cave. Our study highlights that large colonies may provide thermoregulatory benefits that could increase individual fitness. However, aggregations also increase predation costs during emergence. Bats form a column when aerial predator attacks are most frequent. Also, bats seem to adjust their emergence timing in response to seasonal changes in predation risk.

Benthic marine invertebrate herbivores diversify their algal diets in winter

AbstractChanges in the seasonal environment substantially influence organisms. Understanding how species respond to such changes, such as in their feeding interactions and physiology, is key to predicting their resilience to both seasonal and longer term climate changes. The Sitka Sound in Southeast Alaska, USA, is an attractive natural laboratory for studying change, as the marine environment experiences substantial seasonal fluctuations in parameters such as temperature, pH, and productivity between summer and winter. By sampling a suite of dominant macrophyte algae and their benthic herbivores in winter (January) and summer (July) 2019, we investigated how producers and their primary consumers may respond to seasonal change inferred through fatty acid trophic markers. We used a fatty acid logratio selection and analysis approach to ask the following: (1) Do fatty acid biomarkers for algae differ between seasons? (2) Do the same fatty acid biomarkers differ between seasons when applied to herbivores, with herbivore fatty acids tracking the presumed trophic resources? (3) Do fatty acid biomarkers for herbivores differ between seasons, when considered independently from algae? Comparing logratio sets selected each for the algae and the herbivore fatty acids, we found that algae fatty acids were different between our sampling seasons, but the algae‐selected fatty acid logratios did not clearly separate most herbivores by season. In contrast, the herbivore‐selected logratios strongly distinguished herbivore species between the January and June samplings. Further, dispersions of fatty acid logratios were greater within herbivore species in the winter than in the summer, potentially due to the utilization of more diverse resources when preferred algae are less abundant. In total, results suggest that herbivores are not simply tracking the seasonal fatty acid changes in the dominant algae as trophic resources; instead, herbivore fatty acid seasonal changes may occur largely through some other nonexclusive mechanisms, such as omnivory, reductions or shifts in dietary composition, and/or endogenous physiological responses. Thus, the benthic herbivores in our study appear not to be locked into their diets when faced with seasonal change and may use a range of strategies, including diet diversification, to cope with environmental variation.

Light Environment of Arctic Solstices is Coupled With Melatonin Phase-Amplitude Changes and Decline of Metabolic Health.

Light environment in the Arctic differs widely with the seasons. Studies of relationships between objectively measured circadian phase and amplitude of light exposure and melatonin in community-dwelling Arctic residents are lacking. This investigation combines cross-sectional (n = 24-62) and longitudinal (n = 13-27) data from week-long actigraphy (with light sensor), 24-h salivary melatonin profiles, and proxies of metabolic health. Data were collected within the same week bracketing spring equinox (SE), and winter/summer solstices (WS/SS). Drastic seasonal differences in blue light exposure (BLE) corresponded to seasonal changes in the 24-h pattern of melatonin, which was phase delayed and reduced in normalized amplitude (NA) during WS/SS compared to SE. The extent of individual melatonin's acrophase and Dim Light Melatonin Onset (DLMO) change from SE to WS correlated with that from SE to SS. Although similar in extent and direction, melatonin phase changes versus SE were linked to morning BLE deficit in WS, contrasting to evening BLE excess in SS. Seasonal changes in sleep characteristics were closely associated with changes in the phases of BLE and melatonin. Proxies of metabolic health included triglycerides (TG), high-density lipoprotein cholesterol (HDL), TG/HDL ratio, and cortisol. Adverse seasonal changes in these proxies were associated with delayed acrophases of BLE and melatonin during WS and SS. TG and TG/HDL were higher in WS and SS than in SE, and cross-sectionally correlated with later melatonin and BLE acrophases, while lower HDL was associated with later BLE onset and later melatonin acrophase. Overall, this study shows that optimal 24-h patterns of light exposure during SE is associated with an earlier acrophase and a larger 24-h amplitude of melatonin, and that both features are linked to better metabolic health. Improving light hygiene, in particular correcting winter morning light deficit and summer evening light excess may help maintain metabolic health at high latitudes. Novel solutions for introducing proper circadian light hygiene such as human-centric light technologies should be investigated to address these issues in future studies.

Identifying priority conservation areas for threatened amphibian habitats in the Yangtze river Delta region to maintain regional biodiversity.

The complex life cycle traits of amphibians make them especially sensitive to environmental change, and their ongoing conservation requires the maintenance of suitable habitat that accounts for such life cycle characteristics which may impacted by local environmental dynamics arising from climate change and human disturbance. Many existing studies on amphibian habitats disregard this important issue, leading to uncertainty in managing critical habitats. The application of appropriate conservation practices is therefore constrained by the fact that the major factors influencing amphibian habitats, and their spatio-temporal dynamics at different life stages, are poorly understood. In responding to this notable shortcoming, we applied a Bayesian Belief Network model and geographical detector method to identify spatial and seasonal changes in threatened amphibian habitats of the Yangtze River Delta region (YRDR). Our results reveal the relative importance of different environmental factors contributing to spatio-temporal change of threatened amphibian habitats in YRDR. The results highlight the spatially heterogenous nature of amphibian habitats and the impacts of urbanization, as evidenced by quantitative metrics of percentage area of built-up land and distance to built-up land. Habitat conservation priority analyses also indicate the importance of prioritizing habitat restoration efforts in severely degraded areas. Analysis of seasonality indicates that amphibians face particularly severe challenges during their autumn hibernation period (Slope=-0.002). In revealing seasonal variations in the level of threat to amphibians at different life stages across different habitats, this study fills an important knowledge gap and therefore supports regional amphibian habitat conservation and restoration efforts. The results of the study further imply that current conservation strategies need to comprehensively account for seasonal changes, life-cycle stages, and spatial heterogeneity.

Wetland vegetation zoning as a response to groundwater complex systems.

This research investigates the interplay between groundwater flow systems and the zoning of wetland species. We aimed to elucidate the relationship between these factors through comprehensive field evaluations encompassing plant composition, piezometric levels, and flow direction; groundwater chemistry, vertical and horizontal, at different depths (0.15m, 2m, 4m, and 6m) during both rainy and dry seasons. Our findings reveal distinct patterns. The plant diversity in the FP site was related to low ion concentration. In contrast, the dominance of T. geniculata in the TH site correlated with species adapted to sulfate and chloride (SO42- and Cl-) tolerance. In the CTC site, the dominance of C. jamaicense was linked to local groundwater flow and significant surface water inflows. At the same time, T. domingensis prevailed in the TC site due to sodium chloride facie inhibiting C. jamaicense seed germination. Our study highlights the role of groundwater chemical composition in shaping wetland ecosystems by influencing species tolerance and how the spatial distribution of groundwater discharge and seasonal changes contribute to distinct vegetation patches within wetlands. The relationship between groundwater systems, the water's chemical composition, and vegetation is strongly dependent. This can explain mortality and changes in vegetation composition in wetlands in different parts of the world, stressed by climate change effects (rain pattern alteration).